Elizabeth Olsen has a favorite sister, and it's not Mary-Kate!

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"Ashley remembered my birthday"

When it comes to family, you should never admit you have a favorite, as Elizabeth Olsen recently learned when she gave a surprising and honest answer about her sisters.

Photo credit: Daniel Tanner/WENN.com

Elizabeth Olsen has two very famous older siblings, twins Mary-Kate and Ashley Olsen, and when it comes to family, we seldom pick favorites.

However, when the Martha Marcy May Marlene actress was put on the spot during her appearance on Watch What Happens Live on Wednesday, she actually gave an answer as to who her favorite sister is.

A caller rang in to the show and asked the 25-year-old beauty to pick between Mary-Kate and Ashley. According to Us Weekly, the caller said, "You have two sisters, I also have two sisters, you have to prefer one over the other. Who do you like better: Mary-Kate or Ashley?"

The host of the talk show, Andy Cohen, chimed in to try and get Elizabeth to pick. Cohen said, "Now this is a good question. There has to be one that is more in your favor today that you're more vibing on."

What happened next surprised the audience as Elizabeth said, "Ashley remembered my birthday, but I don't hold grudges against Mary-Kate forgetting mine. She was out of town! "

Realizing that she probably should have said nothing about her sibling Mary-Kate forgetting her birthday while on holiday in Jamaica, Elizabeth joked, "I should have just said my brother!"

Cohen was thrilled with his guest's answer and stated, "Ashley's in the lead today, but tomorrow MK could do something amazing."

The Oldboy star wanted the world to know that she loves all her siblings very much though, even if she currently prefers the one who didn't forget her birthday. Elizabeth confessed, "We're all very close! I'm very close with my brother [Trent] as well. I should have just said him. That would have been the easier scapegoat."

"Mary-Kate is literally going to come home from her vacation and shoot me that I said that."

However, Cohen was not done causing trouble and continued to tease his guest, saying, "I think, from the last time I was in Jamaica, text signals do work."

The lesson to be learned here is don't forget your sibling's birthday, even when you are on holiday in Jamaica. Right?

However, Elizabeth isn't holding any grudges and was quick to defend her sister, saying, "Yeah, but how often when you're on vacation do you look at your phone and read the date? You don't really read the date. You're just like, 'This is day three of my vacation.'"